#define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>
int main()
{
	int a = 0;
	int m = 0;
	int n = 0;
	int sum = 0;
	for (a = 1; a <= 100; a++)
	{
		m = a % 10;
		if (m == 9)
			sum++;
	}
	for (a = 1; a <= 100; a++)
	{
		n = (a - m)%10;
		if ( n == 9)
			sum++;
	}
	printf("%d\n"; sum);
	return 0;
}